﻿<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>禁止弹出警告框</title>
    <script type="text/javascript">
        window.alert = function(str) {
            return ;
        }
        alert("看看能不能弹出警示框");
    </script>
</head>
<body>

</body>
</html>